Integer overflow in rgbimgmodule.c in the rgbimg module in Python 2.5 allows remote attackers to have an unspecified impact via a large image that triggers a buffer overflow. NOTE: this vulnerability exists because of an incomplete fix for CVE-2008-3143.12.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.